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Stumbling at low rpms, erratic idle, loss of high RPM power

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Old 05-01-2011, 11:01 AM   #1
Geared
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Default Stumbling at low rpms, erratic idle, loss of high RPM power

All of a sudden.....

erratic low rpm idle

loss of high rpm power

stumbling at low rpms

almost sounds like its missing a little.

car seemed fine when cool...but maybe it was happening a little.

please help asap....im stuck at a friends.

spark plug?

jb
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Old 05-01-2011, 11:14 AM   #2
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Check wires, coil packs, voltage... ect...
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Old 05-01-2011, 11:26 AM   #3
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If you have a stock intake, I would check to make sure the carbon trap hasn't come loose and is blocking airflow.
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Old 05-01-2011, 11:30 AM   #4
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not a stock intake....im going to advanced auto to see if there are codes.
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Old 05-01-2011, 11:35 AM   #5
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Quote:
Originally Posted by C5 Frank View Post
Check wires, coil packs, voltage... ect...
Hey.. sorry to be kinda short... I had my 8 month old son on my lap and couldnt hardly type. It sounds to me like a bad connection with either a splug wire, coil pack.... or your alternator is going bad.
I am sure there are other things it could be too.... maybe an air leak somewhere in your intake. I would check the electronics and the air paths.... Goodluck!
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Old 05-01-2011, 04:56 PM   #6
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I found this.....could this be the culprit, and cause the about described symptoms?

Spark plug wires boot, driver side was laying on header (like alot of people) and while trying to diagnose this issue, I had the car running....and

a small spark occured when I lightly lifted that wire (it touched header)...and I came to find out the boot is cracked.






Could this be it?

How could this cause a near 50% power drop all of a sudden at high rpm?

Last edited by Geared; 05-01-2011 at 05:02 PM.
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Old 05-01-2011, 05:45 PM   #7
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It is going to run poorly on 7 cylinders, yes. So that needs to be fixed. It'll give the p0300 most likely (many scanners can't read the specific codes for which particular cylinder is missing).

Do you have the other codes? If not, I strongly suggest you invest $70 or so in a code reader and keep it in the cubby. I got mine at walmart and I've used it so many times on my and friends cars...it's well worth it.
Be sure and get one that is canbus ready.

The codes will give us clues as to what, if anything, else is wrong.
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Old 05-01-2011, 05:46 PM   #8
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CAR IS THROWING NO CODES.....thats the odd part.
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Old 05-01-2011, 06:35 PM   #9
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That doesn't make sense. You sure the scanner could read a can bus equipped car?

Did you fix the spark plug wire? Still doing it?
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Old 05-01-2011, 07:00 PM   #10
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joe,

havent fixed wire, yet....cannot find any locally at this time on sunday.

i have some duralast wires in the garage...but am skeptical about using them, and i dont know if they would fit this application....i believe they were for my ls6.

jb
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Old 05-01-2011, 07:08 PM   #11
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They will work, give it a shot!
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Old 05-01-2011, 07:24 PM   #12
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only have 7 somehow...must have lost one when i moved...damnit.

can i change just the one?
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Old 05-01-2011, 07:26 PM   #13
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Certainly! Keep us posted.
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Old 05-01-2011, 08:26 PM   #14
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Wow....look at this sucker....the inside copper? or w/e material was "burnt"....not good.





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Old 05-01-2011, 08:43 PM   #15
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It happens when they hit the header for one reason or another. It's no big deal, you didn't hurt the car so don't worry about it.

How's it running?
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Old 05-01-2011, 08:52 PM   #16
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i didnt start her up yet.....

i will in a little bit.

I now want to change out all the wires, its a good excuse to do so....any suggestions?
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Old 05-01-2011, 09:29 PM   #17
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started her up....sounds alot better at idle, no more bouncing rpms....will report tomorrow after i drive for a while

THANKS JOE

Last edited by Geared; 05-01-2011 at 09:33 PM. Reason: idle
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Old 05-01-2011, 09:57 PM   #18
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Happy to help!

I prefer stock wires. Sometimes people get charging system errors with aftermarket wires.

If I was you I'd leave that ls6 wire on and be done with it.

BTW if your car didn't throw a code with that burned wire your tuner must have turned off the p0300 code.
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Old 05-01-2011, 09:59 PM   #19
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joe,

i doubt he turned it off, but its possible....i used a cheap scan tool that may not have properly read the computer - it was the loan a tool scanner from advance auto parts

jb
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Old 05-01-2011, 10:17 PM   #20
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Hey man...get some heat barrier sleeves to protect those boots.
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